In a prior art electric shaver, an inner blade having slots performs a reciprocating motion while sliding over an outer blade to cut beard between them (for example, Japanese Patent laid open Publication H7-250979). A plate sheet, as a main body of the inner blade, has an arch-like (or of inverse-U-character-like) section in a direction perpendicular to the longitudinal direction thereof, and it has a plurality of the slits in parallel to each other, extending from a side wall through the top curved portion to another side wall. An arch-like edge is formed between two adjacent slits, and the edge of the curved portion is a cutting edge. The outer blade is formed so that its inner face makes contact with and slides over an outer face of the inner blade. The outer blade is mounted to a main body of the electric shaver, while the inner blade is connected via a joint to a driver at the top of the main body. The inner blade fixed to the joint so that the outer plane thereof is provided along the inner face of the outer blade, and the joint to which the inner blade is fixed is connected to the driver at the top of the main body, and it is driven so that the longitudinal direction of the inner blade agrees with the direction of the reciprocating motion of the driver. The above-mentioned prior art inner blade has fixing members to the joint at the bottom end at the central portion in the longitudinal direction of the two side walls of the arch-like inner blade.
Some of such electric shavers generate a cutting sound due to vibrations of the edges of the inner blade when the inner and outer blades bite and cut beard between them. The cutting sound or vibration sound of the edges is used to judge the shaving state of beard. In order to judge the shaving state better, the vibration sound might be enhanced by increasing the length of the edges. However, when the fixing members to the joint are provided at the central portion in the longitudinal direction, the lower end of the edges at the central portion cannot be extended lower due to interference of the fixing portions, and the length of the edges cannot be increased. Therefore, the length of the edges cannot be increased as far as the height of the generally U-character-like inner blade is not increased.
The invention intends to solve this problem, and its object is to provide an electric shaver which can enhance the vibration sound by increasing the length of the arch-like edges formed between adjacent slots of the inner blade.